FILE - North Carolina’s senior senator, Richard Burr, a Republican, teamed up with Sen. John McCain, R-Ariz., to pitch a new plan for FBI terror investigations. The amendment failed in the Senate on Wednesday after concerns about expanding the federal government’s ability to spy on certain email and Internet records without a warrant. J. Scott ApplewhiteAP

FILE - North Carolina’s senior senator, Richard Burr, a Republican, teamed up with Sen. John McCain, R-Ariz., to pitch a new plan for FBI terror investigations. The amendment failed in the Senate on Wednesday after concerns about expanding the federal government’s ability to spy on certain email and Internet records without a warrant. J. Scott ApplewhiteAP

Even with some bipartisan support, an effort Wednesday by prominent Republican Sens. Richard Burr of North Carolina and John McCain of Arizona to increase the federal government’s access to some private email data failed in the Senate.

The proposal to broaden the FBI’s authority during terror investigations came up just two votes short and likely will be brought up again by Senate Republican leaders.

Opponents criticized Burr and McCain’s amendment, saying it would encroach on personal privacy and give federal authorities too much power to spy on email records without warrants. The American Civil Liberties Union fought the measure this week.

Senate Majority Leader Mitch McConnell looks to be hoping to bring the legislation back to the floor at another time.

Burr, the chairman of the Senate Intelligence Committee, said in a floor speech that part of the proposal would only reinforce current FBI authority, not expand spying capability. The measure was proposed as an amendment to the Commerce, Justice, Science and Related Agencies Appropriations Act under Senate consideration.

The vote on the amendment was 58-38; it needed 60 votes to move forward. Six Republicans broke from party ranks and voted against the amendment.

The amendment was aimed at allowing the FBI to secretly collect, without court orders or warrants, some email data and internet browser history. Supporters stressed Wednesday that the proposal wouldn’t give federal officials warrant-less power to look at detailed email messages – only ensure access to relevant metadata such as location details, email addresses, dates and times.

Burr and McCain said the amendment would grant FBI officials the ability to adequately investigate terror suspects and perhaps prevent attacks.

During his floor speech, Burr acknowledged that his proposal with McCain probably would not have helped authorities stop recent terror-related incidents in the United States, including this month’s attack at a nightclub in Orlando, Florida, that killed 49 people and wounded dozens.

The failed proposal Wednesday would have given federal officials greater surveillance powers over people labeled as potential “lone wolf” terrorists. That part of the amendment sought to make permanent existing government-access provisions in the Foreign Intelligence Surveillance Act.

Currently, the “lone wolf” provision lets intelligence officials secretly conduct surveillance on people suspected of being terrorists without solid evidence that they have ties to organized terror groups. Without a legislative move to renew or extend the provision in federal law, those FBI powers are set to expire in 2019.

Other parts of Burr and McCain’s proposed amendment would have granted federal agents access to certain email and internet records via “national security letters” instead of warrants. National security letters are a type of subpoena – not a court order from a judge after reviewing evidence – that federal authorities can use to force tech companies to assist in investigations.

Although the measure was defeated Wednesday, it’s likely to come up again.

Republican leaders in the Senate allowed members to cast votes for nearly an hour. As time wound down, Senate Majority Leader Mitch McConnell, R-Ky., changed his vote from “yes” to “no.”

More than likely, McConnell is hoping to bring the legislation back to the floor at another time – after switching his vote, he asked for a reconsideration. Procedurally, he’ll now be able to bring the amendment forward again.

Burr and McCain’s proposal was also backed by Republican Sens. John Cornyn of Texas and Jeff Sessions of Alabama.